Well casing perforator



\ Jan. 31, 12939. E, ALZNER 2,145,231

WELL CAS I NG PERFORATOR Filed Sept. 17, 1937 Patented Jan. 3l, 1939UNITED STATES PATENT OFFICE WELL CASIN G PERFORATOR Egon Alzner,Campina, Rumania, assignor to Shell Development Company, San Francisco,Calif., a corporation of Delaware Application September 17, 1937, SerialNo. 164,351 In Rumania September 24, 1936 7 Claims. (Cl. 164-05) Thepresent invention relates to methods of sired to operate several ofthese devices in seiiring explosive charges in boreholes, and perries,as will be explained below. tains more specifically to a method andappa- The contact head I is provided with a central ratus for explodingthe charges of gun-type casbore I0, having an upper portion of asomewhat 5 ing perforators by means of a gaseous igniting enlargeddiameter. This portion is filled with 5 mixture. packing 6, and isclosed at the top by a cap 2. An Gun-type perforators are vcommonly usedinsulated conductor Illa passes through the cap, whenever, in thedrilling or production of oil packing 6 and bore I0, and is terminatedby an wells, it becomes necessary to perfor-ate a. casing electrode I4,provided with an incandescent l along a certain portion of its length,for example, igniter or spark plug I8. The circuit of the ig- 10 along aportion extending through an oil sand niter I8 is completed through theconnecting pin which had been passed and shut oi by accident 3 to themetallic mass of the perforator. or mistake. The contact head I isattached, by means of Perforators of this type comprise a single or ascrew threads I2 to the connecting member 5, l plurality ofinterconnected body members, each which isin turn attached to the bodymember 9 15 of the latter being usually provided with a pluby means ofscrew threads 2U. A iiuid and gasrality of chambers containingcartridges or eX- tight fit is insured, for example, by means ofproplosive charges by means of which perforating jections 22, provided,if desired, with suitable projectiles are red through the casing.gaskets. These explosive charges are usually ignited by The connectingmember 5 is made in the form 20 electrical means, a priming compositionor detof a hollow cylinder having an internal bore of ronating cap beingused for each separate charge. relatively large diameter, a gasetightpriming The disadvantage of this method consists chamber I6, serving asa housing for the igniter chiefly in the use of a plurality of primingcom- I8, being thereby formed between the contact positions, and in thenecessity of using a relativehead l and the body member 9' 25 ly largenumber of insulated electrical conduc- Thea body. memberl 9 is providedwith a cham'. tors in connection therewith. The numerous ber 3 for theexp Osive Charge said chamber being in communication with any desirednum- ,Senns ard tassags if? thrse tcdulfgfsuliln ber of screw-threadedcylindrical openings prefe O.y o .e per gr or us c y erably arranged atright angles to the axis of 3 made tight agamst mud pressures m thebore' the perforator. The ring barrels 26 and 26a are hole so that theCharging and preparation of screwed into these openings and hold theprojecthese devices for actual use as well as the caretiles 28 and 28%obturation rings 1 and 1a made ful handling required in operationconsumes a of copper or any other Suitable plastic material' relativelylong t1me. are used to tighten the barrels in their nests and 5 It .1S,therefore, the ObJeCt Of this inv'ention to to support the projectileswhereby a provide a gun-type Casing perforatOl 1n which seal is securedwhen said projectiles are in place.

eXDlOSiVe Charges or cartridges are exploded by The explosive chargechamber 34 is in commumeans of a single igniting or priming gaseousnication with the priming chamber I6 by means 40 charge. of a bore 32,which may be of a relatively small 4o The construction of such casingperforators, diameter. and the method of firing the same according Thechamber 34 is closed by means of a plug to the method of this inventionwill be clear I3, having a bore II. from the following description takenwith refer# The cap member I5 is screwed onto the body ence to theattached drawing, which gives a. member 9 by means of screw threads 36,and 45 cross-section elevation view of a preferred emhas a central boreholding a non-return check bodiment of the present device. valve 38.'I'his bore may be tightly closed from Referring to the drawing, theperforator comthe outside by means of the screw plug 40. prises acontact head I, a connecting member 5, The perforator is prepared foroperation as a body member 9, and a cap member I5, all cast follows: Thering barrels 26, holding the pro- 5 and/or machined of any suitablemetal. jectiles 28 are rst screwed into the openings The contact head Iis' provided with external provided therefor in the body member 9. Thescrew-threads 8, by means of which the perfora can member I5 is thenunscrewed, and the plus tor may be attached to suitable suspending I3removed from the body member 9. An explomeans, or to another perforatorwhen it is desive charge, such as smokeless powder. pyroxylin, 55

etc., is then inserted into the chamber 3l, whereafter the plug i3 andcap l5 are replaced,'the plug 40 being removed from the latter. Acornpressor or a tank containing any suitable explosive gas mixtureunder pressure is then connected to the cap member i5. This mixture maycomprise air and hydrogen, air and a suitable hydrocarbon gas, etc. Thecompressed gas passes through the non-return valve n, the bore II inplug i3, and illls the explosive chamber u. passing thereafter throughbore l! to illl the igniting chamber i8. Although, as stated above, thechamber I4 may already have been iilled with a solid explosive,'thegaseous mixture will pass without difilculty between the porous massAformed by the grains or akes of said explosive. Likewise, ii theperforator had been loaded with explosive sticks or an explosivelcartridge, which is especially advantageous to secure quick operation,the gases will easily pass through the interstices between said sticksor cartridge and the walls o! the chamber 3l.

After the perforator has been illled with explosive-gases to a desiredpressure, the cap member is again closed by means oi plug 40, any escapeo! gases from within the perforator being prevented by the packing 6,rings and projectiles 1 and 28, and the check valveJl. The insulatedconductor I 0a is then connected to a source of electric current throughan open switch or a ccntact device, such, for example, as described inPatent No. 2,059,488 to Prikel, and the perforator is lowered by anysuitable means to the place where it is desired to perforate the casing.The

switch or contact device is then closed, and the v igniter or spark plugIl ignites the explosive gaseous mixture in chamber i6, the explosionbeing transmitted through bore 32 to the explosive in chamber 434, whichis in turn exploded and drives the projectiles 28 through the casing.

It must be noted that in some cases the use of a solid explosiveinchamber 34 may be entirely dispensed with, both chambers I6 and 34 beingillled only with the explosive gas mixture, which operates in such casesboth as an igniting and as a driving charge. I

I! it is desired to operate a plurality of peri'orators connected inseries, the following procedure may be followed.

Assuming that a top perforator T is to be operated in series with a'bottom perforator B, the cap member i5 is removed from the perforator T,while the cap 2, packing 8, conductor lila and electrode i4 are removedfrom perforator .'B. The two perforators are then loaded withprojectiles and solid explosive in the ordinary manner, after which theyare screwed together on top of each other, the screw threads 8 ofperiorator B engaging the screw threads 36 of perforator T.

The perforators are then filled with an explosive gaseous mixturethrough the valve 38 of perforator B, said mixture passing to theperforator T through the unobstructed passage i0. The charges in bothperforators are exploded by means of the igniter I8 of perforator T.

It is understood that the present invention is in no way limited to theembodiment described above, but broadly embraces a method of ilring agun type casing perforator by igniting a gaseous mixture conned in saidperforator, said gaseous mixture serving either as a priming charge fora separate explosive charge placed in a space permeated by said gaseousmixture, or as a driving charge capable of forcing projectiles throughthe desired target.

It is also understood that, should it be so desired, the gaseous mixturemay be exploded by means other than electrical, for example, by means ofa priming cap located in chamber i8 and lired by any suitable method,such, for example, as by dropping a go devil on top of the perforator. i

I claim as my invention:

ll. In the process of tiring projectiles from a gun-type casingperforator, coniining a solid explosive charge in an atmosphere formedby an explosive gas within the perforator, and igniting said gas toexplode the solid explosive charge.

2. In a gun-type casing perforator, a housing, a gas-tight chamberwithin the housing, tiring barrels held by the housing in communicationwith the chamber, projectiles adapted to form a gas-tight seal withinthe barrels, means for coniining an explosive gas charge in the chamber,and means for igniting said gas charge.

3, In a gun-type casing perforator, a housing, a gas-tight chamberwithin the housing, iii-ing barrels held by the housing in communicationwith the chamber projectiles adapted to form a gas-tight seal within thebarrels, means for placing and retaining a solid explosive charge withinthe chamber, means for conning a gaseous explosive charge within thechamber, said gaseous lcharge surroundingsaid solid charge, and meansfor igniting said explosive gas charge.

4. In a gun-type perforator, a housing, a iirst and a second gas-tightchamber within the housing, a communicating passage between thechambers, firing barrels held by the housing in communication with thesecond chamber, projectiles adapted to i'orm a gas-tight seal within thebarrels, means for placing and retaining a solid explosive charge withinthe second chamber, means for confining a gaseous explosive chargewithin the ilrst and the second chambers, said gaseous chargesurrounding said solid charge, and means within the iirst chamber forigniting said gaseous explosive charge.

5. In the process of perforating a well casing, igniting an originallygaseous charge for simultaneously discharging a plurality oi projectilesagainst said casing.

6. In the process of perforating a well casing, using an originallygaseous igniting charge for simultaneously firing a plurality ofexplosive charges capable of driving a plurality of projectiles throughsaid casing.

7. In a gun-type casing perforator, a housing forming a gas-tightchamber, cylindrical oriiices communicating between said chamber and theoutside through the walls of the housing, projectiles adapted to form agas-tight seal within said orifices, means for confining an explosivegas charge in the chamber, and means for igniting said gas charge.

EGON ALZNER.

